Polycrystalline silicon rod
AssigneeMitsubishi Materials Corporation
InventorRyoichi Kaito
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Abstract
A polycrystalline silicon rod comprises a seed rod made of polycrystalline silicon, and a polycrystalline silicon deposit which is deposited on the outer circumferential surface of the seed rod by the CVD process. A diameter of the polycrystalline silicon rod is 77 mm or less. When the polycrystalline silicon rod is observed by an optical microscope with respect to the cross section perpendicular to an axis of the seed rod, needle-shaped crystals each having a length of 288 μm or less are uniformly distributed radially with the seed rod being as the center in the polycrystalline silicon deposit. The needle-shaped crystals account for 78% or more of the cross section.
Claims7
A polycrystalline silicon rod comprising a seed rod made of polycrystalline silicon, and a polycrystalline silicon deposit which is deposited on an outer circumferential surface of the seed rod by the CVD process,
- wherein a diameter of the polycrystalline silicon rod is 77 mm or less,
- wherein when the polycrystalline silicon rod is observed by an optical microscope with respect to across section perpendicular to an axis of the seed rod, needle-shaped crystals each having a length of 288 μm or less are uniformly distributed radially with the seed rod being as the center in the polycrystalline silicon deposit, and
- wherein said needle-shaped crystals account for 78% or more area of the cross section.
A polycrystalline silicon rod comprising a seed rod made of polycrystalline silicon, and a polycrystalline silicon deposit deposited on an outer circumferential surface of the seed rod by the CVD process,
- wherein a diameter of the polycrystalline silicon rod is above 77 mm,
- wherein when the polycrystalline silicon rod is observed by an optical microscope with respect a cross section perpendicular to an axis of the seed rod, needle-shaped crystals each having a length of 291 μm or less are radially and uniformly distributed with the seed rod being as the center in the polycrystalline silicon deposit, and
- wherein said needle-shaped crystals account for 15% to 35% area of the cross section within a region having a diameter of 127 mm.
Dependencies are inferred from the claim text.